LM1851 Unisonic Technologies, LM1851 Datasheet - Page 4

• Manufacturer Part Number: LM1851
• Description: Ground Fault Interrupter
• Manufacturer: Unisonic Technologies

UTC LM1851
AC ELECTRICAL CHARACTERISTICS
Normal Fault Current Sensitivity
Normal Fault Trip Time
Normal Fault with Grounded Neutral
Fault Trip Time
Note 2: Average of 10 trials.
Note 3: Required UL sensitivity tolerance is such that external trimming of UTC LM1851 sensitivity will be necessary.
Note 4: This externally applied current is in addition to the internal ''output drive current '' source.
CIRCUIT DESCRIPTION
feedback path status signal (V
sits quiescently at three times its threshold value, I
rapidly removed. When a fault current, I
operational amplifier, A1, uses feedback to force a virtual ground at the input as it extracts I
during either half-cycle will cause V
the timing capacitor during both half-cycles of the line, I
exits pin 2. Thus during one half-cycle I
discharges it. When the capacitor voltage reaches 17.5V, the latch engages and turns off Q3 permitting I
the gate of an SCR.
UTC
Note 1: For operation in ambient temperatures above 25℃, the device must be debated based on a 125℃
The UTC LM1851 operates from 26V as set by an internal shunt regulator, D3. In the absence of a fault (I
maximum junction temperature and a thermal resistance of 80℃/W junction to ambient for the DIP and 162/W
for the SO Package.
PARAMETER
+
-
UNISONIC TECHNOLOGIES CO., LTD.
A
300mV
S
) is correspondingly zero. Under these conditions the capacitor discharge current, I
(Refer to Block and Connection Diagram)
Ct
0.002
S
FIGURE 1.Normal Fault Sensitivity Test Circuit
to go high, which in turn changes I
Figure 1 (Note 3)
500Ω Fault, Figure 2 (Note 2)
500Ω Normal Fault, 2Ω Neutral,
Figure 2 (Note 2)
f
f
-I
, is induced in the secondary of the external sense transformer, the
Iss
1k
TH
31V
TEST CONDITIONS
charges the timing capacitor, while during the other half-cycle I
LINEAR INTEGRATED CIRCUIT
7
5
8
1
TH
TIMING
CAP
SCR
TRIGGER
OP AMP
OUTPUT
Vcc
(Ta = 25 °C, Iss=5mA)
, so that noise induced charge on the timing capacitor will be
f
only charges the capacitor during the half-cycle in which I
1.5M
R
GND
+IN
SET
-IN
1
from 3I
2
3
4
6
100k
MIN
TH
3
to I
800Hz
0.047μF
TH
TYP
. Although I
18
18
5
f
. The presence of I
MAX
7
TH
QW-R122-007,A
discharges
2
UNIT
f
to drive
mA
ms
ms
=0) the
4
TH
1
,
f
f